Ore variability management at Mamatwan manganese mine for an improved sinter product

Abstract

Geological and more specifically mineralogical inconsistencies in solid solution variations within natural ore deposits creates processing difficulties in metal production chains. Mamatwan mine established in 1963 produced manganese ore without addressing such geological variability, as the focus at that stage was on the ore production only, with the resulting Mamatwan mine facilities developed to reflect this production requirement. Changes in product requirements led to expansion of the Mamatwan mine product range by adding a Sinter Plant. A Dense Medium Separation (DMS) facility was also added to manage the mentioned variability of Mamatwan ore and subsequent sinter product. DMS facilities require significant resources to operate, while also generating significant waste (+/-40% of ore treated via the DMS is discarded - ore containing 36% and less manganese becomes tailings). The operational costs of DMS and the waste it generates initiated a search for an alternative variability management methods other than the DMS, that would be less resource and waste-generation intensive. This dissertation presents a literature review of possible ore variability management strategies, as well as methods and procedures that would generate the necessary data to determine whether a possible alternative to the DMS could be used at Mamatwan mine. A modified Stuart Pugh method was used for the development and Selection of the best Blend Mining trial option. Pugh method modifications comprised dedicated taxonomy to decrease ambiguity during Option Selection. Trial Concept Option Development and Selection methods were implemented to provide an optimum solution for the validation and verification of Blend Mining as an ore variability management method. More than 18000 tons of sinter was produced as part of the trial. Chemical compositions were determined for samples extracted at pre-selected sampling points at Mamatwan Mine. From the trial study, it was proven that Blend Mining has the ability to manage ore variability present in Mamatwan manganese ore. If implemented at Mamatwan mine, Blend Mining could render annual operational savings of roughly R40m. The lack of waste-generation is an additional benefit brought about by Blend Mining, which further contributes to total efficiency of the mine, as well as the implied maximisation of the Mamatwan ore resource. Differently stated, Blend Mining would facilitate an increased life-of-mine (LOM) for Mamatwan mine.